Journal of The Japan Society of Electrical Machining Engineers
Online ISSN : 1881-0888
Print ISSN : 0387-754X
ISSN-L : 0387-754X
Volume 16, Issue 32
Displaying 1-6 of 6 articles from this issue
  • Relationship between Effect of Heat Treatment and Stress Distribution
    Yoshitsugu MUKOYAMA, Isao OGATA, Masahiko HIHARA
    1983 Volume 16 Issue 32 Pages 1-14
    Published: March 31, 1983
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    In electric discharge machining (EDM), as the residual stress that generates on surface of the workpiece has direct effects upon the quality of products, more detailed investigations are required.
    In previous papers, the relationships between the residual stress distribution and the electrical conditions (energy supplying duration, peak discharge current), the materials of workpiece (mild steel, cold work die steel) and machining forms (impulse and repetitional discharge machining) etc, were reported by the same authers.
    The residual stress generated on EDM surface is mainly caused by thermal stress and transformation stress resulting from thermal action of electric discharge. Accordingly, the magnitude and contribution form of stress are closely related to the mechanical characteristics and metallic structure of the workpiece. Therefore, it is very important to make clear the relation between the residual stress and heat treatment processes of the material (workpiece).
    This paper examined the distribution form of residual stress with a main point to the tempering effects after hardening in the case of the cold work die steel, and discussed the cause for generation of residual stress being observed the cross section of the workpiece (machined by EDM) employing scanning microscope.
    Download PDF (5250K)
  • Ryutaro MAEDA, Kunio CHIKAMORI, Hideo YAMAMOTO
    1983 Volume 16 Issue 32 Pages 15-24
    Published: March 31, 1983
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    The effect is investigated of pulsed current conditions, i. e. pulse period and duty factor, on feed rare of wire electrochemical machining.
    Dependence of feed rate on pulsed current conditions can be explained by assuming that the feed rate is restricted by instantaneous maximum value of reaction products concentration in the electrode gap. The feed rate can be improved by applying shorter pulse period than the residential time of the electrolyte; W/v (W; thickness of workpiece, v; electrolyte velocity), and by applying the larger duty factor, although using direct current is not necessarily favorable.
    Periodic disturbance is sometimes found in pulsed current form, when the feed rate is near its limit value. This disturbance is attributed to the periodic change of products concentration.
    Download PDF (732K)
  • Masahiko FUKUI, Natsuo KINOSHITA
    1983 Volume 16 Issue 32 Pages 25-36
    Published: March 31, 1983
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    Of late years, the performance of Wire EDM has improvid and become almost equal to that of Grinding. In order to improve the performance of Wire EDM moreover, it is necessary to investigate the wire electrode throughly. There is no paper, however, which deals with the characteristics of the wire electrode in Wire EDM. This study is for the purpose of developing a new wire electrode which has good performance in Wire EDM. In this paper, the working characteristics of various ally wire electrodes were examined. And about the wire electrodes which have good performance, the cause of the superiority was searched.
    Download PDF (3662K)
  • Tsutomu FUJIMURA, Kohji ISUZUGAWA
    1983 Volume 16 Issue 32 Pages 37-44
    Published: March 31, 1983
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    In the performance of electric discharge forming, the discharging gap, as the impulsive pressure source, is often bridged with a fine metal wire prior to occurrence of an impulse current. The quantity of energy released into the dischargingg gap in CLR-Gap series circuit has a maximum if the voltage drop across the gap is approximately equal to the half of the starting voltage of capacitor. the gap of the length satisfying the condition above is usually too large to be breaked down without a fuse-wire. The principal effect of the fine metal wire may be striking of an arc in the gap. The energy poured into the wire to melt and vapourize it must, however, have the effect on the forming.
    This paper reports experimental studies of the effect of the fusewire on the bulging in free-forming. Rectangular impulse currents were used to supply engery into the under-water discharging gap, and lead wire segments were used as fuses in the gap. Aluminium sheets were bulged in free-forming, and the hights of bulges were examined on basis of the previous discussion.
    The bulging hight, h, may be expressed as follows:
    h2=K{kE(QaQ00)-ΔQ}
    where, K=k1/(k2+Ta), ΔQQ0+kQTa,
    Qa: amount of discharge in arc,
    Ta: duration of arc,
    ΔQ00: apparent increase of amount of discharge in arc, which is caused by the energy poured into the wire segment.
    Download PDF (2621K)
  • [in Japanese], [in Japanese]
    1983 Volume 16 Issue 32 Pages 45-48
    Published: March 31, 1983
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    Download PDF (355K)
  • [in Japanese]
    1983 Volume 16 Issue 32 Pages 49-52
    Published: March 31, 1983
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    Download PDF (321K)
feedback
Top